slawson2000 on Fri August 10, 2012 6:51 PM

After many years and a couple handfuls of successful projects thanks to what I learned last time I posted and from what I could look up on the site, I am back with another one.

2002 Jetta. The A/C seems to work kind of while driving. It is definitely cool, but not cold. At a standstill it blows warn air, maybe 5 deg cooler. I have not opened the hood yet to get readings (that will be tomorrow), but I wanted to try and get some preliminary info.

My guess is that it is a little low on refrigerant. I remember complaints last year that it was cool, not cold. After I look for leaks, what should I be charging this up to? Is there a hi/lo target? I have read that this either does or may have a variable condenser and they are finicky. Most posts I saw suggested filling from a vacuum, if that is the only way to do it how much does it take?. I did not see anything about just adding a little. Apparently the A/C has never been serviced.

Any comments or thoughts? Anything specific I should start with or look for?

slawson2000 on Sat August 11, 2012 9:32 AM

Cussboy on Sat August 11, 2012 4:23 PM

Measure you high and low side pressures at about 1500 rpm, and post them here, before you add any refrigerant.

slawson2000 on Wed August 15, 2012 10:12 AM

The pressure was about 150/15, I added a little and now it is around 195/25. It is blowing cool, but not consistently. I have not driven it but was told that it was not as cold after driving around a little, then it would get cold again. Hmmm....

slawson2000 on Thu August 16, 2012 9:48 PM

Well, an oddity. It seems to take a while for it to start blowing cold and when the car stops moving, it tends to blow warm air. The radiator fans are both blowing. Any ideas?

mk378 on Thu August 16, 2012 10:10 PM

Like HECAT said you need to charge by weight then evaluate performance. Variable compressors do strange things when not properly charged. Until you know the charge is right (by weight) you're just forever guessing whether it is the charge amount or something else.

slawson2000 on Fri August 17, 2012 11:02 AM

I am also checking for leaks. I will recharge but have a question. those 12 oz cans... is that 12oz of weight or 12 fluid oz's?

AutoCool on Fri August 17, 2012 2:54 PM

Refrigerant capacity is always stated/measured by weight whether it's stated in ounces or grams. Hope you get your AC working again.

mk378 on Fri August 17, 2012 3:37 PM

The cans are filled by weight.

Leggie on Sat August 18, 2012 12:38 AM

QuoteOriginally posted by: slawson2000So no way just to add a little?

Also, how would I get to 27oz with 12oz cans?With a marker, a $20 0.05 or 0.1oz scale from eBay, simple math and patience. You need to weigh every can and mark them before use. Subtract weight of empty ones. Just because cans say 12oz doesn't mean there's precisely 12oz in there. sometimes they leak. Sometimes they have an ounce or so too much. Don't assume its 12.0oz in there.

In the US, it's easier with R12 than R134a. Can hookup for 134a is much better than R12 and you can store partially used cans for a long time. Don't trap any liquid R134a in hose, because you'll cause an error.